From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8520EC433E6 for ; Tue, 26 Jan 2021 10:30:35 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2D20023108 for ; Tue, 26 Jan 2021 10:30:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2D20023108 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 733B089B67; Tue, 26 Jan 2021 10:30:34 +0000 (UTC) Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by gabe.freedesktop.org (Postfix) with ESMTPS id 3D76589B67 for ; Tue, 26 Jan 2021 10:30:33 +0000 (UTC) IronPort-SDR: LOu4AdbyworobGcmfNb2kXUD9Bx9/QIjC++Eaw1bMP4jfAEGJUV/3T6O68OYffBxowIAf50mSL thSB8JeFWUAg== X-IronPort-AV: E=McAfee;i="6000,8403,9875"; a="264703878" X-IronPort-AV: E=Sophos;i="5.79,375,1602572400"; d="scan'208";a="264703878" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Jan 2021 02:30:29 -0800 IronPort-SDR: LAxL0S65jZQ1wpDfte0QZaLdgV6o9nMmMFvihiINmT+U7kdvmoH1X5GI+oRGIm1FXbNmHsRcDI u3TGSCP3kzcg== X-IronPort-AV: E=Sophos;i="5.79,375,1602572400"; d="scan'208";a="369059401" Received: from shogg-mobl.ger.corp.intel.com (HELO mwauld-desk1.ger.corp.intel.com) ([10.252.19.250]) by orsmga002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Jan 2021 02:30:27 -0800 From: Matthew Auld To: intel-gfx@lists.freedesktop.org Date: Tue, 26 Jan 2021 10:30:19 +0000 Message-Id: <20210126103019.177622-1-matthew.auld@intel.com> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH] drm/i915/buddy: document the unused header bits X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" The largest possible order is (63-PAGE_SHIFT), given that our min chunk size is PAGE_SIZE. With that we should only need at most 6 bits to represent all possible orders, giving us back 4 bits for other potential uses. Include a simple selftest to verify this. Signed-off-by: Matthew Auld Reviewed-by: Chris Wilson --- drivers/gpu/drm/i915/i915_buddy.c | 3 ++ drivers/gpu/drm/i915/i915_buddy.h | 7 ++- drivers/gpu/drm/i915/selftests/i915_buddy.c | 48 +++++++++++++++++++++ 3 files changed, 56 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_buddy.c b/drivers/gpu/drm/i915/i915_buddy.c index 20babbdb297d..3a2f6eecb2fc 100644 --- a/drivers/gpu/drm/i915/i915_buddy.c +++ b/drivers/gpu/drm/i915/i915_buddy.c @@ -48,6 +48,8 @@ static struct i915_buddy_block *i915_block_alloc(struct i915_buddy_block *parent { struct i915_buddy_block *block; + GEM_BUG_ON(order > I915_BUDDY_MAX_ORDER); + block = kmem_cache_zalloc(global.slab_blocks, GFP_KERNEL); if (!block) return NULL; @@ -56,6 +58,7 @@ static struct i915_buddy_block *i915_block_alloc(struct i915_buddy_block *parent block->header |= order; block->parent = parent; + GEM_BUG_ON(block->header & I915_BUDDY_HEADER_UNUSED); return block; } diff --git a/drivers/gpu/drm/i915/i915_buddy.h b/drivers/gpu/drm/i915/i915_buddy.h index ed41f3507cdc..9ce5200f4001 100644 --- a/drivers/gpu/drm/i915/i915_buddy.h +++ b/drivers/gpu/drm/i915/i915_buddy.h @@ -15,7 +15,9 @@ struct i915_buddy_block { #define I915_BUDDY_ALLOCATED (1 << 10) #define I915_BUDDY_FREE (2 << 10) #define I915_BUDDY_SPLIT (3 << 10) -#define I915_BUDDY_HEADER_ORDER GENMASK_ULL(9, 0) +/* Free to be used, if needed in the future */ +#define I915_BUDDY_HEADER_UNUSED GENMASK_ULL(9, 6) +#define I915_BUDDY_HEADER_ORDER GENMASK_ULL(5, 0) u64 header; struct i915_buddy_block *left; @@ -34,7 +36,8 @@ struct i915_buddy_block { struct list_head tmp_link; }; -#define I915_BUDDY_MAX_ORDER I915_BUDDY_HEADER_ORDER +/* Order-zero must be at least PAGE_SIZE */ +#define I915_BUDDY_MAX_ORDER (63 - PAGE_SHIFT) /* * Binary Buddy System. diff --git a/drivers/gpu/drm/i915/selftests/i915_buddy.c b/drivers/gpu/drm/i915/selftests/i915_buddy.c index 632b912b0bc9..f0f5c4df8dbc 100644 --- a/drivers/gpu/drm/i915/selftests/i915_buddy.c +++ b/drivers/gpu/drm/i915/selftests/i915_buddy.c @@ -727,6 +727,53 @@ static int igt_buddy_alloc_range(void *arg) return err; } +static int igt_buddy_alloc_limit(void *arg) +{ + struct i915_buddy_block *block; + struct i915_buddy_mm mm; + const u64 size = U64_MAX; + int err; + + err = i915_buddy_init(&mm, size, PAGE_SIZE); + if (err) + return err; + + if (mm.max_order != I915_BUDDY_MAX_ORDER) { + pr_err("mm.max_order(%d) != %d\n", + mm.max_order, I915_BUDDY_MAX_ORDER); + err = -EINVAL; + goto out_fini; + } + + block = i915_buddy_alloc(&mm, mm.max_order); + if (IS_ERR(block)) { + err = PTR_ERR(block); + goto out_fini; + } + + if (i915_buddy_block_order(block) != mm.max_order) { + pr_err("block order(%d) != %d\n", + i915_buddy_block_order(block), mm.max_order); + err = -EINVAL; + goto out_free; + } + + if (i915_buddy_block_size(&mm, block) != + BIT_ULL(mm.max_order) * PAGE_SIZE) { + pr_err("block size(%llu) != %llu\n", + i915_buddy_block_size(&mm, block), + BIT_ULL(mm.max_order) * PAGE_SIZE); + err = -EINVAL; + goto out_free; + } + +out_free: + i915_buddy_free(&mm, block); +out_fini: + i915_buddy_fini(&mm); + return err; +} + int i915_buddy_mock_selftests(void) { static const struct i915_subtest tests[] = { @@ -735,6 +782,7 @@ int i915_buddy_mock_selftests(void) SUBTEST(igt_buddy_alloc_pathological), SUBTEST(igt_buddy_alloc_smoke), SUBTEST(igt_buddy_alloc_range), + SUBTEST(igt_buddy_alloc_limit), }; return i915_subtests(tests, NULL); -- 2.26.2 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx